OK, here's an interesting one. On my iPad, I purchased "Text Plus", an app that let's you text with a number they provide. I did a wipe on my iPad when I sent it in for repair. I want to use text plus from my iMac, so I went into the app store here on my iMac, and searched "Text Plus", and nothing comes up. Is the app store on the iPad the same as this one?

All I can determine is that you have never actually synced your iPad to iTunes on your Mac, and thus iTunes has no idea that you've ever bought any apps. You could try signing in to your iTunes account, that may make a difference.

In iTunes Preferences under the General tab there are a bunch of check boxes that let you choose which items appear in your Library list. There is a box for Apps, just make sure it's checked off.

In fact, whenever an application isn't behaving the way you need it to, always take a look at the Preferences menu and see what options you have there. Very often that's where you'll find your solutions. The options are almost always very neatly organized and intuitive. Don't be afraid to delve into them (along with System Preferences) and try out different ways to make things more efficient for you.

All I can determine is that you have never actually synced your iPad to iTunes on your Mac, and thus iTunes has no idea that you've ever bought any apps. You could try signing in to your iTunes account, that may make a difference.

I did that too after you mentioned it. I think it may have opened options for me that weren't there before.

I don't have an iPad but maybe you need to tell iTunes to sync the apps. With the iPad plugged in, click on it in the Devices list in iTunes. There may be an option there that enables and disables syncing of apps.